Harness Engineering: from CC to AI coding

A full book on harness engineering ('from Claude Code source code to AI coding') with Chinese and English editions in book/ and book-en/. The single best conceptual source in this corpus: chapters on prompt assembly, tool design, context management, verification loops, and sub-agent patterns.

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Key takeaways

• 01

  The harness - not the model - is where coding-agent quality is won

• 02

  Chapters map 1:1 to buildable subsystems: prompts, tools, context, verification

• 03

  Verification loops are treated as non-negotiable, not optional polish

Flows built on this research

Harness Engineering

Verification Loops: Never Trust an Unrun Edit

Wire verification into your agent so every edit is checked by machines - syntax, tests, behavior - before it counts as done.

4 steps · 60-100 minutes

Agent Architecture

Error Recovery and Retry Policy for the Agent Loop

Design the retry, backoff, and give-up behavior that separates production agents from demos that loop forever.

4 steps · 60-90 minutes

Harness Engineering

Cost Control: Model Routing and Effort Tiers

Route work to the cheapest model that can do it and match reasoning effort to task difficulty - with quality guardrails.

4 steps · 90-120 minutes

Agent Architecture

From CLI Harness to Product

Grow a working agent loop into a product: sessions, config, resumability, and the packaging polish the successful terminal agents share.

5 steps · 90-150 minutes

Agent Architecture

Assemble a System Prompt Like the Pros

Structure your agent's system prompt the way leading harnesses do: layered sections, dynamic context, and enforceable rules.

4 steps · 60-90 minutes